The design process for LSIs generally comprises the steps of function design, logic design, circuit design and layout design which are followed in the stated order. One design step is proceeded using design part data produced in its previous design step. Usually respective CAD tools are prepared to aid designs of the respective steps, and the designs are made based on the respective CAD tools. This completed design part data for LSIs are managed individually for the respective CAD tools.
Recently LSIs tend to have increasingly more applications, and the demand for the so called ASICs (Application Specific Integrated Circuit) has been increased. ASICs require relatively large scale circuits to be designed according to users' requirements in short periods of time. As a countermeasure to this, semiconductor device makers use a system in which they provide users libraries with a substantial amount of LSI design part data for respective CAD tools, and the tool users select required design part data out of the libraries and combine them to design their intended LSIs. In other words, semiconductor device makers keep a substantial amount of LSI design part data as what may be called parts, and users select data representing their required parts and combine the data into their intended LSIs.
LSI fabrication processes have made technical progress year by year, and efforts have been made to improve performance of integrated circuits and to further micronize the same. In accordance with performance improvements of integrated circuits, and micronization thereof, individual parts for the fabrication of ASICs, i.e,, LSI design part data, have to be revised. Newly improved CAD tools as well are available. To follow the latest CAD tools, it is necessary to revise LSI design part data to be provided in libraries.
As mentioned above, it is necessary that libraries of LSI design part data are prepared for the respective design steps and for respective CAD tools. In addition, plural design part data are interrelated with one another, and operations of revising the design part data are very complicated. A latest version is based on revising old design part data, and since users do not always use design part data of the latest version, it is necessary to keep plural versions of design part data. Besides, each design part data has a large amount of information. The management of design part data is accordingly very complicated and difficult.
On the other hand, when users make ASIC designs, they want information as to respective parts. Semiconductor device makers provide users with various information as to respective parts in a data sheet or a data book which is a collection of data sheets. With reference to provided data sheets, users are informed as to functions, characteristics, structures, etc. of respective parts, from which to make their intended ASIC designs.
But there are a number of parts to be used in ASIC designs, and users are provided with data books having large amounts of information. Users have to do cumbersome work to obtain information they require. Further, all data they require are not always contained in data books. For example, circuit characteristic values (setup times, hold times, etc.) contained in data books generally include safety margins for operating associated parts. When users require more precise characteristic values to design ASIC, they cannot obtain their essential information from the data books. On the other hand, semiconductor makers have to modernize their data books every time design part data are revised, and have to distribute them to users.